Electric-motor controller.



No. 742,933. PATENTED NOV. 3, 1903.

- W. N. VANCE.

ELECTRIC MOTOR CONTROLLER.

APPLICATION FILED JULY 2, 1902.

NO MODEL. 5 SHEETS-$111231 1.

J .ZZibrrzeya No. 742,933. PATENTED NOV. 3,1903.

W. N. VANCE.

ELECTRIC MOTOR CONTROLLER.

- APPLICATION FILED JULY 2,1902.

N0 MODEL. 5 SHEETS-SHEET 2.

No. 742,933. PATENTED NOV. 3, 1903. w. N. VANCE.

ELECTRIC MOTOR CONTROLLER.

APPLICATION FILED JULY 2:1902.

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7HE NORRIS PETERS ca, PHOTO-L\THD.WASH1N No. 742,933. PATENTED NOV. 3,1903. W. N. VANOEL.

ELECTRIC MOTOR CONTROLLER.

APPLICATION FILED JULY 2, 1902.

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wrnws No. 742,933. PATENTED NOV. 3, 1903. W. N. vVANCE.

ELECTRIC MOTOR CONTROLLER.

APPLICATION FILED JULY 2, 1902.

N0 MODEL. 5 SHEETSS-SHEET 5.

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UNITED STATES Patented November 3,

PATENT OFFICE.

IVALTER N. VANCE, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE MIEHLE PRINTINGPRESS AND MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

ELECTRIC-MOTOR CONTROLLER.

SPECIFICATION forming part of Letters Patent No. 742,933, dated November3, 1903.

Application filed July 2, 1902. Serial No. 114,056. (No model.)

To aZZ whom it may concern:

Be it known that I, WALTER N. VANCE, a citizen of the United States,residing in Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in Electric-Motor Controllers, ofwhich the following is a specification.

This invention relates to improvements upon the style of controllerknown as the railway type, in which the motion of the motor iscontrolled by means of a series of stationary contact fingers and aseries of movable contact-points, the latter arranged in successivepositions to be brought into action by a handle, and in which also thereversing mechanism or cylinder for reversing the direction of the motoris operated by a separate or second handle.

The object of the invention is principally to provide for safety inoperation, to so construct the controller that the motor cannot bereversed by it until the current is off, and so that thecontrolling-cylinder cannot be moved by its handle when thereversing-cylinder isin the off position, and so that the current cannotbe applied when the shuntfield is unexcited, and so that in starting themotor any external resistance in the shuntfield circuit shall beshort-circuited, and so that the current will be automatically cut offeither bya failure of voltage or by a predetermined amount of overloadand the controller-cylinder automatically returned to the off positionby such failure or overload, and to provide an automatic brake broughtinto action by placing the controller-handle in the off position or in aposition beyond the off position, said brake consisting of a current ofelectricity generated by the momentum of the motor itself or themechanism which it drives in their continued movement after the currentis cut off, whereby the motor becomes momentarily a generator, and thecurrent which it thus generates is dissipated in resistance, retardingand stopping the movement, whereby the ordinary friction-brake devicesmay be wholly or partly dispensed with and the motor be made to act asits own brake; and the present invention consists in the novel parts anddevices and novel combinations of parts and devices herein shown ordescribed.

In the accompanyingdrawings, which form a part of this specification,Figure 1 is a front elevation of the improved controller, the casing orhousing being removed; Fig. 2 is a cross-section of the controller,taken on line 2 2 of Fig. 1. taken on the line 3 3 of Fig. 1. Fig. 4 isa detail view of the method of fastening the cover to the machine. Fig.5 is a vertical cross-section of the controller, taken on the line 5 5of Fig. 1. Fig. 6 is a fragmentary section on the line 6 6 of Fig. 5.Fig. 7 is a detail view of the magnetically -operated latch of theno-voltage releasing device. Fig. 8 is a cross-sectional detail on theline 8 8 of Fig. 5. Fig. 9 is a vertical section 011 the line 9 9 ofFig. 7. Fig. 10 is a development of the surface of thecontrolling-cylinder, in which said surface is supposed to be unrolledOrfiattened out. Fig. 11 is a similar development of thereversing-cylinder, and Fig. 12 is a diagram of circuits suitable forthe operation of the device.

Fig. 3 is a similar section In the accompanying drawings like charactorsof reference designate like parts wherever made use of in the severalfigures.

In said drawings, 21 represents the frame work of the mechanism, whichdoes not materially differ from that employed in the ordinarycontrollers of this type.

22 is a movable sheet-metal housing provided with a head 23, rivetedthereto at the lower end. This housing at the upper end sets under aflange 24 on the framework and is held in position by two lugs 25 25,one at each side, which enter the slots 26 in the framework. The lugsare given a dovetail configuration, as shown, and when inserted in theslots a thumb-screw 27 for each slot is screwed up, and the lugs thuslocked against withdrawal, the whole constituting a simple and securemethod of uniting the casing to the framework in such manner that it maybe easily applied and removed when desired.

29 is the controller-shaft, mounted to turn loosely in hearings on theframework, provided with a squared end 30 to receive the handle 31 andprovided also next the handle with the index-finger 32, secured to theshaft to turn therewith. The index itself is marked on the upper head ofthe framework in the usual manner, being lettered to indicate the ofl"position, as is customary in controllers of this type, and in thepresent invention preferably further provided with a mark to'designatethe braking position of the handle if the same shall not be coincidentwith the off position. Rigidly attached to the shaft is the star-wheel33, the periphery of which is cut with double-inclined notches toreceive a springheld roller 34. The roller is pivoted in a forked lever35, which is fulcrumed at 36 to theframework of the machine. Said leveris held yieldingly to the wheel by the spring 37. (See Fig. 2.) Thepurpose of this star-wheel and its roller-pawl is to position the shaftin the operation of the handle and is the customary construction forthis purpose. The star-wheel has an uncut portion 38 in itsperiphery,which not being provided with inclined sides operates as apositive stop to prevent the shaft being turned in either directionbeyond this part. The notches in the star-wheel correspond to the pointson the dial.

The cylinder, which carries the successively-arranged contact-points andwhich is carried by the said shaft 29, is constructed as follows: On theupper portion of the shaftisa shoulder39, below which is the flangedcollar or cylinder-head 40, fitted to turn on the shaft. Fastened tothis collar at the cylindrical part of the collar is the tube 41,whichextends entirely through the cylinder and is supported at its other orlower end on a second flanged collar 42, which surrounds the shaft andis adjustably secured thereto by a set-screw 43, tapped through thecollar-and setting against the shaft. In the space between the tube 41and the shaft is placed a long coiled spring 100, one end of which issecured to the collar 42 and the other end to the collar 40, theconstruction being such that the torsional stress of the spring may beadjusted by turning the collar42 until therequired amount is reached andthen fixed at that amount by fastening said collar by means of theset-screw 43. The direction of winding of the coiled spring is such thatit tends to throw the collar and whatever it carries over with acircular motion in the direction from left to right, as the hands of aclock move in the upperarc of its dial. The lower end of the tube 41 isscrewthreaded and provided with a followernut Around the outside of thetube is a layer of insulating material 45, and outside of this is thecast-iron part 46 of the cylinder and also the portions 47 and 48. Allthese parts 46, 47, and 48 are thus united to the tube 41 in such manneras to be electrically insulated therefrom, but to move therewith as asolid Whole. The parts 47 and 48 are insulated from each other and alsofrom the other parts by the insulating-washers 49 5O 51, and thecast-iron part 46 is also insulated from the following nut by theinsulating-washer 52. The rings 47 and 48, as shown, are provided withexterior brass bands 53 54, which it may be desirable to renew whenworn; but, if preferred, said rings may be made in one solid piece. Thecast-iron body part 46 is out into a number of parts by deep grooves.The purpose of the grooves is to permit the placing of asbestos or otherrefractory insulation between the adjacent contact points and fingers toprevent arcs from being formed across.

On the surface of the cast-iron body part 46 are mounted the contactsfor controlling the armature-circuit in whatever arrangement of themmaybe desired, one arrangement being shown in the development atFig. 10.These contact points are on the drawings marked in succession 55 56 5758 59 60 61 62 63 64. Each contact-point is connected electrically tothe metal ring which supports it. The surface of said metal ringsadjacent to said contact-points, and preferably all the way around, arecovered with a band of varnished asbestos or other insulating material65 as a guard against the maintenance of any are which may be formedupon breaking contact between said contact points and the springcontact-fingers, which latter are now to be described. The springcontactfingers may be of any ordinary construction, insulated from eachother and from the framework of the machine; but I prefer to make themof a special form shown in the drawings, in which 66 is thecontact-finger, supported by the spring 67 from the split collar6S,whicl1 carries the binding-post 69, in which the circuit-wire 70 issecured, and the stop 101, the latter to limit the motion of the fingers66 when not on the contact-point. This apparatus as a whole is securedto the rod 71 of insulating material by being slipped over the end ofsaid rod, and the screw 72, being tightened, binds the split collarsecurely to the rod in any desired position,and so that the springfingermay be adjusted laterally in proper position or turned more or less togive greater or lesser pressure of contact. To the contact finger 66 andadjacent to the contactsurface thereof is secured an insulating-pad 73,preferably of varnished asbestos and which is intended to serve as anarc-guard.

Between the collar 40 and star-wheel 3 is the magnet 74, which issecured mechanically to the collar 40 and moves therewith, and by meansof said rings and the contact-fingers bearing thereon the magnet isenergized at all times when the motor is operatively connected to thecircuit. In the construction shown this is accomplished by connectingthe fingers 66 and the magnet which is connected between theirrespective rings in series with the shunt-field, which is energized atall times when the motor is operatively connected to the circuit. Byarranging a gap in the periphery of these rings to break contact withthe fingers 66 successively, the connection being maintained in eachcase by the subsidiary fingers 66 through a certain amount of resistanceconnected between 66 and 66 these two rings 47 and 4.8 afford'two speedchanges beyond the normal in addition to their function of carryingcurrent to the magnet 74:.

If, as is sometimes the case, it is preferable to connect the magnet 74directly across the line, this can of course be done by winding themagnet to a sufficiently high resistance and making the properconnection. 75 is the armature of the magnet 74, said armature beingpivoted to a part or collar 33, connected to and moving with the shaft29, and springs 78 are arranged so as to normally uphold or swing upwardthe armature 75. To the free end of this armature is fixed a pivotedlatch 76, which when the armature is down, as by the magnet 74beingenergized, engages a projection 77 on the collar 40, which collar,it will be remembered, is loose on the shaft 29, but rigidlyconnected-to the controller-cylinder. By this arrangement andconstruction of parts it will be seen that when the handle 31 is turnedin such direction as to apply current to the motor or to accelerate thespeed in the motor the armature 75 by means of the latch 76 will engagewith the projection 77 on the controller-cylinder and cause saidcontroller-cylinder to be moved with the shaft, provided the magnet isthen energized,and the armature-latch thereby held in engagement.

The object of pivoting the armature 75 and latch 76 is so that when themagnet 75 is deeuergized the armature will rise, and latch 76 will offerno resistance to the instant return movement of the part 77 under theinfluence of the coiled spring. The latch 76 being pivoted, it will beseen that as soon as the armature 75 is denergized the part 77, being nolonger held by anything, will begin to move or rotate under theinfluence of the coil-spring 100, for the latch 76 is free to swing awayon its pivot, and consequently said latch will ofier absolutely noobstruction to the movement of the part 77 except when the armature 75is held close down and under the full influence of the magnet, at whichtime the latch cannot swing, because its tailpiece in an effort to swingwill then come into contact with the upper surface of the part 77. Thelatch itself should of course be made of some non-magnetic metal, asbrass. The magnet 74: being energized, the cylinder moves with theshaft, being driven in the one direction by the engaged latch 76 and inthe other by the torque of the spring, or, in the case of failure ofthat, by the permanent projection 76 on the armature, which alwaysextends far enough to engage the projection 77, and thus drive thecylinder; but if from any cause the magnet 74 is deenergized, the latchno longer restraining or driving the cylinder, the spring will force itto return instantly to the initial or off position, independent of theposition or state of motion of the handle.

to limit the motion and receive the blow of the projection 77 on thecylinder.

To start the motor, it is now necessary to bring the handle back to theinitial or off position, where the latch 76 on armature 75 may engagethe pole projection 77. To prevent adhesion of the armature to the part77,which it will be understood constitutes the polepiece of the magnet,it is preferable that there should be, as shown in the drawings, aslight airgap left between the armature and the said pole-piece when thearmature is fully down, and this may be effected by any de sired form orstop to limit the movement of the armature in this direction, and itwill be seen also that as this engagement of the latch with theprojection depends upon the existence of the circuit through the magnetthe handle cannot be connected to the controller-cylinder in such manneras to again move it until current to the motor is reestablished. Themagnet 7st is of course not strong enough to attract the armaturethrough any greatdistanceandis,infact,not strongenough to attract saidarmature into contact with the projection. Hence I provide the camshapedspring 79, against which the armature strikes when the handle approachesthe off position and which forces the armature down until the latchengages with the projection, after which when the magnet is againenergized it will be held down by the magnet.

The foregoing constitutes an automatic safety appliance which alwaysinsures the controller-cylinder being returned automatically to the offposition whenever the current to the motor ceases, independently of theposition of the controller-handle. Consequently the operator may alwaysknow that the motor cannot start up except when the handle has beenmoved, and this will prevent many accidents which are liable to occur inthe absence of such safety appliance. Moreover, the existence of thisdevice in the controller obviously makes it possible to put thecontroller in the off position by a mere pushbutton or switch in anypart or place in a proper circuit-wire that may be carried to all partsof the machine or machinery to always be in reach of theworkman in caseof emergency or which may be operated automatically, if desired. Thismay be done either directly by such a push-button or indirectly by meansof a relay and auxiliary battery-circuit. Itis also desirable in amachine of this character that when an excessive overload occurs fromany cause-such, for example, as an obstruction to the movement of themachinery or from the operator attempting too rapid an acceleration instarting-tl1at current should quickly be cut off from the armature, andit is especially desirable that this should be done by restoring thecontroller to the off position rather than by merely breaking thecircuit at an auxiliary contact, and this I ac- A cushioned buffer 104is provided tcomplish as follows: The shaft 25) is made &

hollow and a rod 80 passed up through it to slide freely. When this rodis pushed upward with sufficient force, it will strike against a pin 102on the armature and release the latch by physically overcoming theattraction of the magnet, and this will of course permit the coiledspring to throw the controller-cylinder into the off position, just thesame as the deenergization of the magnet '74: would do. To move this rodat the proper time, I provide a magnet 81, which is in the form of asolenoid, the armature of which is in position to strike the bottom ofthe rod when the solenoid is excessively energized by a currentsufficient to lift the armature 82 from the position in which it standsadjusted. The rod 80, while free to slide in the shaft, is frictionallyheld therein, preferably by giving the rod a slight bend, so that it isself-supporting and does not come in contact with the armature of thesolenoid until said armature is lifted by the action of the magnet, theobject being to cause the armature of the solenoid to strike the rod ablow, which is imparted at the upper end of the rod to thelatch-armature of the magnet 74, such a blow being sufficient to detachthe armature '75 against the magnetic influence which holds it down. Thesolenoid 81 being connected in series with the armature-current of themotor carries at all times the current of the armature, and the armatureof the solenoid is so adjusted as to position that the normalarmature-current of the motor will not energize the solenoidsufficiently to cause it to lift the solenoid-armature 82; but when apredetermined excess of current passes through the solenoid on accountof the excessive overload to be guarded against then the solenoid willinstantly lift its armature 82 and cut off the controller, and thus stopthe motor. The adjustment of the position of the solenoidarmature 82 iseffected by means of the adjusting-screw 83, against which thesolenoidarmature 82 rests by its own weight. When this screw is turnedupward, the solenoid will respond to a lesser excess of current, andwhen the screw is turned downward it will not respond until a greaterexcess of current exists.

Between the spring-fingers 66 and the metal framework of the machine isarranged the blow-out magnet 84, the pole-piece of which is formed,preferably, of a projection from the iron framework of the controller.The pole-piece is formed with two ridges 85, which by reference to Fig.8 it will be seen are located so as to concentrate the lines of force ofthis magnet at each end of the contact portion of the springcontact-fingers 66. A covering of varnished asbestos 86 over this magnetserves as an arc-guard. It will be seen that the lines of force from thepole projections are directly across the path of any are which may beformed when the contactfingers 66 leave the contact-points on the cyl-The magnet 8a is an clectromagnet inder.

teases and is connected in the armature-circuit of the motor, so that itis energized by the same current that forms the arc to be extinguishedat all times when the motor is running. It has been found that such ablow-out magnet will not successfully eliminate the arc unless it bevery strongly excited, and hence it takes a very considerable amount ofenergy to effeet the object; but I have found that the presence of themagnets 74 and 81 when properly connected as to the direction of thecurrent through them may be made to aid the blow-out magnet verymaterially, and thus.

lessen the amount of energy consumed thereby. To accomplish thispurpose, the magnets M and 81 should be wound or connected to thecurrent in such manner as to present similar poles to each other whichare opposite to the pole presented by the blow-out magnet 84. This givesa direction to the lines of force of said magnets 74 and 81 such thatthey coact with the lines of force of the magnet 6t and materiallyincrease its effectiveness in blowing out or extinguishing the arc, sothat the controller thus arranged is found to be practically arcless.

Parallel to the controller-cylinder is the usual reversing-cylinder 87,which is or may be constructed in all respects as is customary incontrollers of the railway type. It is provided with the customaryhandle 88 and index-finger 89 and has any usual form of spring-detentfor holding it in position. The novel feature in respect to this deviceconsists in the mechanism for interlocking the reversing-cylinder andthe controlling-cylinder to prevent the operator from reversing thecurrent while the controller is in the on position and also to preventthe movement of the controller-handle while the reverserhandle is in theoff position. This I accomplish as follows: In the shaft 90 of thereversing-cylinder two rounded or beveled sockets 9i 92 are cut, (seeFig. 3,) and in the shaft 29 a similar single socket 93 is out. A rod94,with rounded ends, is provided and extends from the controller-shaftto the reversing-shaft and is made just long enough, so that whenentered fully, say, in the socket 92, it will just clear the socket 93and when fully entered in the socket 91 it will also just clear saidsocket 93 or when fully entered in the socket 93 it will just clear thesockets 91 and 92. This rod is supported in perforations which passthrough the stationary bearings of the two shafts, and is consequentlyfree to slide endwise, but cannot be moved sidewise. Nowsupposing theaffairs to be in the position shown in Fig. 2 and the end of the rodfully inserted in the socket 92, it will be seen that the shaft 29 canbe moved freely; but if turned at all the socket 93 will be moved awayfrom the end of the rod and the solid surface of the shaft presentedthereto, so that the rod is no longer free to slide endwise, and whilein this connection it will be impossible to move the shaft 91 of thercversingcylinder; but if the shaft 29 is in the position shown in Fig.2 and the socket 93 opposite to the end of the rod, which position, itshould be stated, is the off position of the controller, thenthereversing-shaft can be rotated, because an effort to rotate it willsimply force the rodout by the cam action of the socket 92 and the rodwill be free to slide into the socket 93 on the controller-shaft; butwhen this takes place the controller-shaft is thereby locked. Thus itwill be seen that the movement of either shaft locks the other and alsothat while one is locked the other is free to move. The socket 92corresponds to the ahead position and socket 91 to the back or reverseposition of the reversing-cylinder, and when either one of these socketsis opposite to the end of the rod 94: the controllershaft is free tomove; but itcannot be moved except when the controller-shaft is in thisoff position. This mechanism while absolutely certain in action isentirely free from springs and levers, and is therefore exceedinglydurable and cannot get out of order.

The automatic self-acting brake is constituted as follows: Upon any oneof the rings of the controller-cylinder except the lowermost one or thetwo uppermost'onesthat is to say, upon any one of the rings which areemployed to introduce armature resistance- I affix an extracontact-point 95 and locate it so that it will come in contact with thespringfinger corresponding to that ring only when thecontroller-cylinder is in the off position. This extra contact-point 95is insulated from the ring which carries it, and from it an electricalconnection 96, is led to the ring 18, which by its spring-finger isconnected at all times while the motor is running to one side or other(according to the direction the motor is running) of thearmature-circuit, and as all of the spring-fingers below the ring 18 areconnected to the opposite side of the armature-circuit the result isthat when the controller-cylinder is in the off position and any one ofthese spring-fingers rests upon the extra contact point 95 thearmaturecircuit is complete in itself, but cut off from the line or itssupply of electricity. Consequently if the motor continues to run of itsown momentum alone, or of its own momentum, assisted by the momentum ofwhatever machinery ormoving partsit is mechanically connected to thisfurther movement will cause the motor to act as a separately-excitedgenerator and generatein said armature-circuitacurrentof electricitywhich will be dissipated in the form of heat in whatever resistance saidcircuit includes, and as this extra contactpoint 95 maybe placed uponany one of the rings of the controller specified it is obvious that theamount of resistance in this braking-circuit may be predetermined tosuit any requirement. This changing of the motor into a temporaryseparately-excited generator will always take place when the controlleris put in the off position, and

consequently the act of throwing the controller-handle into the offposition will thus automatically apply the brake, and the braking actionwill, moreover, always be in proportion to the speed of the motor whenthe brake is applied and the action of braking will always be a uniformretardation, and as the braking action depends entirely upon the dynamicaction of the momentum of the motor and other moving parts the mereplacing of the controller-handle in the OE position when the motor andmachinery are at rest will not operate to set or fix or put intooperation any brake which requires to be released before the machinerycan be set in motion. It sometimes happens, of course, that when themachinery is at rest and the controller-cylinder necessarily in the offposition it is desirable to turn the machinery by hand or otherwise forsome purpose of examination or repair, for example, and in such case theturning of the machinery or motor by hand or very slowly will tend togenerate the braking-current; but I find that such slow motion willgenerate so slight a current and produce so slight a braking action asnot to interfere practically with this slow sort of turning; but if itshall ever be found to interfere by reason of the size of the motor orby the way in which the motor is geared this can be remedied by simplyputting the handle of the reversing-cylinder in the off position, whichwill operate to entirely disconnect the armature.

In the diagram shown at Fig. 12, represents the motorin this case amotor of the compound type. 111 is a series of resistancecoils, theterminals of which are brought to the contact-fingers of the cylinder.These resistance-coils are adapted to be introd uced in thearmature-circuit of the motor. 112 and 113 are other resistance coils.These are adapted to be inserted in the shunt field-circuit of themotor, and their terminals are brought to the fingers, which bear on therings 47 and 48 of the cylinders. 114 is the circuit through theno-voltage magnet 74, connected from the ring 47 to the ring 48. 115 isthe circuit through the overload-magnet 81, one of its terminals beingconnected to the armature of the motor and the other to the blow-outmagnet 84:, the circuits around said blow-out magnets being shown at116, one terminal being connected as above described and the otherterminal to the bottom of the ring of the controller-cylinder andpassing through whateverof the resistance 111 may be in circuit and thearmature of the motor. 117 and 118 are the two bindingposts forconnecting the circuit system herein shown to the circuit of the dynamo,said dy namo or source of electric energy not being shown on thediagram.

I claim- 1. The combination of the controller-cylinder provided with itssuccessively-arranged contacts, the blow-out magnet placed adjacent tosaid contacts, and the two latch-operating magnets placed at each end ofthe controller-cylinder, all three of said magnets being so wound andconnected that their lines of force cooperate to extinguish the are orarcs formed at the contacts, substantially as specified.

2. The combination with the controllershaft and reverser-shaft, of thelocking device consisting of a rod sliding in supports between the twoshafts and cam-shaped cavities in the two shafts, said rod having itselfcam-shaped ends, substantially as specified.

3. In a controller device operated by a handle, the combination of themovable part which carries the contacts, an electromagnet connected tosaid part, and an armature connected to said handle, said armaturehaving a catch adapted to engage the movable part while theelectromagnet is energized and to release it when deenergized; withmeans operating to return the contacts to the initial or off positionindependently of the handle when the armature is denergized,substantially as described.

4. In a controller device, the combination of a shaft operated by ahandle, a rotatable part carrying the contacts, and a latch connected tosaid shaft and adapted tolock said shaft to said part, an electromagnetconnected to the contact-carrying part and adapted to hold said latch inlocked position While energized and to release it when deenergized, andmeans operating to return the contactcarrying part to its initial or offposition when said latch is released, substantially as described.

5. In a controller, the combination of a shaft operated by a handle, amovable part carrying a series of contacts, an electromagnet having itscoils mounted on said movable part and its armature connected to theshaft, a latch connected to said armature adapted to lock said part tosaid shaft, and means for returning the contacts to the initial or offposition when said latch is released, said armature holding the latch inengagement while said magnet is energized, and releasing said latch whenthe magnet is deenergized, substantially as described.

6. In a controller having one part operated by a handle, and anothermovable part carrying contacts, the combination of a latch connectingsaid parts, and a spring, operating to return the contact-carrying partto the initial or off position when said latch is released; with anelectromagnet having its coils connected to one part and its armatureconnected to the other part, said armature holding the latch inengagement While the magnet is energized and releasing said latch whenthe magnet is deenergized, substantially as specified.

7. In a controller, the combination of a part operated by a handle, anda part carrying the movable contacts, and an electromagnet having itscoil fast to one part and its armature fast to the other part; with alatch pivoted to said armature and adapted to connect said parts whenthe magnet is energized, and a spring operating to return the movablecontacts to the initial or off position independently ot' the handlewhen said latch is released, substantially as described.

8. In a controller, the combination of a movable part carrying contacts,a shaft operated by a handle, and a latch adapted to lock the shaft andpart so that the movement of the handle in one direction may move saidmovable part; with an electromagnet having its coils connected to thesaid part, and its armature connected to the shaft, said armaturecontrolling said latch, substantially as described.

9. In a controller, the combination of the movable handle, a movablepart which bears the contacts, a coiled spring connecting said handleand part under tension, and a latch connecting said part with thehandle, said spring operating to return the contacts to the initial oroff position when said latch is released; with means for releasing thelatch, comprising an electromagnet, and its armature and connectionswhereby the said armature disengages the latch when the electromagnet isenergized, said magnet being adjusted to act upon passage of anexcessive current, substantially as described.

10. In a controller, the combination of a rotatable shaft, a movablepart bearing the contacts, a latch connecting said part with said shaft,and means adapted to return the movable contacts to the initial or offposition when said latch is released, and two electromagnets forreleasing the latch, one magnet having its coils connected to themovable part, and its armature connected to the shaft, said armatureoperating to release said latch when the coils are deenergized from afailure of the common source of current; and the other magnet operatingto release said latch when excessively energized by a high current,whereby the contacts will betautomatically returned to the initial oroff position, either when the current from the common source fails, onthe one hand, or there is an excessive overload on the other,substantially as specified.

11. The combination of the controller-cylinder provided with itssuccessively arranged contacts, the blow-ont magnet placed adjacent tosaid contacts, and a latch-operating magnet placed at one end of thecontroller-cylinder, both said magnets being so wound and connected thattheir lines of force cooperate to extinguish the are or arcs formed atthe contacts, substantially as specified.

12. The combination with the controllershaft and reverser-shaft, of alocking device consisting of a rod sliding between the two shafts andadapted to engage cams on either of the shafts to lock one when theother is shifted, substantially as specified.

13. In a controller, the combination of a rotatable shaft, a series ofcontacts rotatably mounted thereon, and a series of fixed contactsadapted to engage with the rotatable contacts when the latter are turnedin one direction; a catch adapted to lock theshaft to the rotatablecontacts, and means for normally keeping the latch out of engagement;with an electromagnet having one member fast to the contacts and itsother member fast to the shaft, and arranged to hold the catch inengagement when energized, said magnet being in electrical connectionwith the main circuit, and means forautomatically returning the movablecontacts to off position when the magnet is deenergized and the latchthereby released, substantially as described.

14. In a controller, a rotatable series of contacts, a rotatable shafthaving an operating-handle, a spring connected to the shaft andcontacts, and adapted to rotate the latter relatively to the former, anda catch adapted to lock the shaft to the contacts; with an electromagnetand the trip-rod actuated thereby and adapted to unlock the catch, whenthe magnet is energized by an excessive current, thereby permitting thespring to return the contacts to off position, substantially asdescribed.

15. In a controller, the combination of a rotatable shaft, a series ofcontacts rotatably mounted thereon, and a series of fixed contactsadapted to engage with the rotatable contacts when the latter are turnedin one direction, a catch at one end of the series of contacts adaptedto lock the shaft to the rotatable contacts, and means for normallykeeping the latch out of engagement; with an electromagnet adjacent tothe catch and adapted when energized to hold the catch in engagement,and a second electromagnet at the other end of the contacts and atrip-rod actuated by said second magnet adapted to engage and releasethe catch when such magnet is energized by an excessive current, andmeans for automatically returning the movable contacts to off positionwhenever latch is released, substantially as described.

16. In a controller, the combination of the shaft and handle, thecylinder rotatably mounted on said shaft carrying the movable contacts,and a helical spring surrounding the shaft within the cylinder andconnected thereto so as to rotate the cylinder on the shaft; with alatch for locking the shaft to the cylinder, and an electromagnet havingone part fast to the cylinder and another part fast to the shaft, saidmagnet controlling said latch and holding the same in engagement whenenergized, and a second electromagnet and devices actuated therebyadapted to release said latch when said second magnet is energized by anexcessive current, substantially as described.

17. In a controller, the combination of a rotatable hollow shaft, acylinder rotatably mounted on the shaft and carrying the movablecontacts, a spring connecting the cylinder and shaft and adapted to turnthe former on the latter, a latch for locking the shaft to the cylinder,a rod within the hollow shaft adapted to release the catch, and anelectromagnet adapted to actuate said rod, substantially as described.

18. In a controller, the combination of a rotatable hollow shaft, acylinder rotatably mounted on the shaft and carrying the movablecontacts, a spring connecting the cylinder and shaft and adapted to turnthe former on the latter, a latch forlocking the shaft to the cylinder,a rod within the hollow shaft adapted to release the catch, and anelectromagnet adapted to actuate said rod when energized by an excessivecurrent, andasecond electromagnet adapted to hold the latch inengagement when energized, and means for releasing the catch when thesecond magnet is de'e'nergized, substantially as described.

19. In combination, the controller-cylinder provided with successivecontacts, a blow-out magnet adjacent to said contacts, thelatchoperating magnet, and the overload-magnet adjacent to saidcylinder, said latch and overload-magnets being arranged and adapted toassist the blow-out magnet in preventing and extinguishing arcs,substantially as set forth.

IVALTER N. VANCE.

\Vitnesses:

II. M. MUNDAY, L. LINDAUER.

